Integrating Planning Theory with Socio-Ecological-Technological Systems for Urban Flood Risk Management: A Case Study of Chiba Prefecture, Japan

Abstract

Urban flooding presents increasingly complex challenges exacerbated by climate change, rapid urbanization, and aging infrastructure. This investigation combines planning theories and socio-hydrological modelling to create a planning-adaptable urban flood management strategy. The case study of Chiba Prefecture, Japan, demonstrates this approach in depth. By applying the Social-Ecological-Technological Systems (SETS) framework in combination with planning theories, the study has identified the relationship between the conventional engineered methods and the newly introduced environmentally friendly (nature-based) solutions. Our findings, which are based on content analysis of 23 official statutory planning documents, indicate that there is a significant focus on the conservation of ecosystems and green infrastructure balanced with issues of emergency planning and community engagement. One of the points that the results highlight is integrating the ecological, social and technological aspects in order to create flood management policies that are both robust and fair. This integrated approach offers a robust framework for mitigating flood risks while promoting sustainable urban development and long-term community resilience.

1. Introduction

Urban flooding has become one of the most crucial problems in the 21st century—a complex threat which has been deepened by climate change, rapid urbanization, and old infrastructure. For a lot of cities all over the world, the traditional engineering steps such as dams, levees, and channel improvements are not enough to cope with the complicated interplay between human systems and natural hydrological processes. This insufficiency is being demonstrated most in places that are vulnerable to floods such as Chiba Prefecture, Japan, where several times the floods have shown the need for new, integrated management solutions. The geographical vulnerability of Chiba Prefecture is made more apparent by its flat land, areas with a high population concentration, and being in the path of typhoons and heavy rains. The weaknesses have been exposed clearly by the recent incidents. In the region, some areas broke the record of rainfall in September 2023 (Figure 1). In Mobara City, rainfall reached 391.5 mm in 24 h, exceeding previous records; the floods that followed caused a lot of damage both to structures and to the area’s facilities [1]. In addition, a heavy downpour in the northwest of Chiba in July 2024 led to the inundation of 17 houses in Ichihara, thereby illustrating not only the repeat nature of the hazard but its socio-economic aspect as well [2]. Traditional flood mitigation efforts in Chiba have focused on structural defenses. These efforts often fail to capture the dynamic interplay between human behavior, land use, and hydrological processes—a gap that socio-hydrology seeks to address by examining the reciprocal interactions between society and water systems. Integrating planning theory into socio-hydrological models offers a promising avenue for overcoming these limitations. By incorporating concepts such as resilience, sustainability, and public participation, planners can design adaptive strategies that mitigate flood impacts and enhance long-term community well-being.

This study aims to bridge the gap between conventional flood management practices and emerging integrated approaches in urban planning. Focusing on Chiba Prefecture provides an empirical foundation to explore how planning frameworks like the Social-Ecological-Technological Systems (SETS) model can inform and transform socio-hydrological strategies. The objective is to develop a more comprehensive paradigm that harmonizes engineered interventions with nature-based solutions, paving the way for more robust, adaptive, and equitable flood mitigation policies. This research contributes to the evolving discourse on urban resilience and offers valuable insights for policymakers, urban planners, and disaster management engineers confronting similar challenges globally.

2. Theoretical Framework

Historically, Chiba Prefecture’s flood management strategy has relied heavily on structural solutions such as levees, dams, river channel improvements, and flood storage basins. These engineered measures have been designed to redirect and contain floodwaters, thereby protecting urban centers and critical infrastructure from the immediate impacts of heavy rainfall and typhoons. While effective in reducing flood damage, these physical barriers often entail high costs and extensive maintenance, sometimes leading to unintended environmental degradations (e.g., altering natural drainage patterns and impacting local ecosystems). As the intensity and frequency of extreme weather events increase due to climate change, these limitations have become more pronounced, prompting planners to reconsider a purely structural approach and pivot to explore more integrated flood management strategies.

Complementing traditional physical defenses, Chiba is increasingly adopting non-structural measures that address the socio-ecological dimensions of flood risk. Under the SETS framework, non-structural strategies encompass policy reforms, comprehensive land use planning, zoning regulations, and robust community education on flood hazards. Nature-based solutions, such as the restoration of wetlands, preservation of natural floodplains, and installation of green infrastructure (e.g., vegetative buffer zones, permeable pavements, and urban green spaces), play a critical role in this context. These strategies help absorb and slow down floodwaters, enhance local biodiversity, provide long-term ecological benefits, and reduce vulnerability and exposure. This shift toward nature-based and community-focused solutions aligns with global trends advocating for sustainable, adaptive, and locally tailored flood management measures.

A comprehensive examination of disaster-related literature indicates that utilizing the SETS keyword coding analysis provides a robust framework for comprehending the complex dynamics of catastrophe resilience and management. Numerous studies have utilized this paradigm to elucidate the intricate interactions among policy, infrastructure, and environmental issues. Hong and Tanaka [3] present a comparative analysis that clarifies how integrating various dimensions can reveal inconsistencies in disaster policy responses, whereas Lee and Hong [4] enhance the discourse by concentrating on urban disaster management via a sophisticated SETS-based approach. Similarly, Chang et al. [5] utilize a SETS learning framework to assess urban flood resilience, diligently collecting essential keywords from policy documents to reflect geographical and temporal fluctuations. Markolf et al. [6] illustrate that interconnected assessments of social, ecological, and technological systems can reveal underlying theme tendencies that traditional techniques may miss. Ahern [7] and Chester et al. [8] have made foundational contributions that enhance our comprehension of infrastructure robustness and climate resilience, a viewpoint further developed by the bibliometric analysis of Meerow and Newell [9]. Our analysis utilizes a novel, balanced keyword coding methodology that enhances prior frameworks and incorporates nuanced contextual interpretations, building on this extensive academic foundation and providing a unique contribution to the assessment of disaster policies.

Recent papers are mainly focusing on combining planning theory with socio-hydrology to manage urban flood risks [10,11]. The most advanced research builds complex socio-hydrological models that integrate flooding simulation, human behavior as well as adaptive management policies for the community and urban resilience improvement [12,13]. Urban planners are now experimenting with combining practical land use planning tools, stakeholder engagement, and participatory processes to account for the positive influence of planning theory concept frameworks on flood prevention policy. Such cases not only confirm our approach and showcase the world’s leading practices for the design of flexible, collaborative, and evidence-based flood management strategies but also support the authenticity of these best practices [14].

While the SETS framework provides a valuable lens for analyzing the interconnections among social, ecological, and technological dimensions in flood management, its scope is inherently limited in capturing the full spectrum of policy dynamics and stakeholder interactions [5]. We have integrated a range of planning theories into the analysis of flood management in Chiba Prefecture to address these limitations. Rational planning offers a systematic approach for evaluating cost-effectiveness and risk assessments of engineered interventions, while incremental planning emphasizes the need for flexibility and iterative policy adjustments in response to evolving environmental threats [15]. Advocacy planning ensures that the interests of vulnerable populations are foregrounded, and communicative planning facilitates the collaborative dialogue necessary for building consensus among diverse stakeholders; radical and collaborative planning advocates for transformative, community-based strategies and inter-agency coordination. Nuanced insights into political, social, and participatory processes inform the SETS classification [16]. By also considering these planning theory models, policymakers can overcome the intrinsic limitations of SETS alone. Flood management strategies that are more adaptive, inclusive, and resilient are more capable of addressing the complex challenges posed by urbanization and climate change.

This study builds on established planning theory to critically analyze flood management policies in Chiba Prefecture by emphasizing three interrelated dimensions: resilience, sustainability, and public participation. Resilience is a system’s capacity to absorb disturbances, adapt to changing conditions, and reorganize following shocks—a concept enriched by Folke et al. [17] and further explored by Walker and Salt [18]. In flood management, this means preventing floods, minimizing their impact, and fostering rapid recovery through adaptive policy mechanisms. Sustainability involves meeting present needs without compromising the ability of future generations to meet their own, requiring the balancing of economic, social, and environmental goals. This challenge has been increasingly addressed through water-sensitive urban design and nature-based solutions as outlined by Wong and Brown [19]. Nature-based solutions are also enhanced by integrating stakeholders’ perceptions and preferences [20]. One of the significant factors of nature-based solutions [21] is public participation. Drawing on Arnstein’s [22] seminal work as well as the collaborative planning approaches of Forester [23] and Innes and Booher [24], this factor emphasizes the engagement of diverse stakeholders. Such involvement enhances the legitimacy and effectiveness of flood management by integrating local knowledge and fostering trust among policymakers, technical experts, and community members.

The Panarchy framework developed by Gunderson and Holling [25] informs the integration of planning theory with socio-hydrological models. This framework provides a lens to examine the dynamic cycles—growth, conservation, release, and reorganization—that characterize coupled human–water systems. For Chiba Prefecture, it offers a means to assess how urban growth strategies, sustained infrastructure investments, emergency responses during flood events, and post-disaster policy revisions work together within an evolving adaptive system. Insights from social learning and collaborative planning theories underscore the necessity of ongoing stakeholder dialogue and iterative policy development. Recent contributions from Sivapalan et al. [26] and Du et al. [27] further support the view that integrating technical, ecological, and social strategies is essential for constructing resilient urban flood management frameworks. Together, these theoretical perspectives provide a robust foundation for understanding and enhancing the adaptive capacities of flood management policies in Chiba Prefecture.

Integrating planning theory with socio-hydrological models advances our understanding of urban flood management as a dynamic interplay between human decisions and natural systems. The Panarchy model [25] is particularly valuable for this analysis, as it frames flood management policies in cyclical phases—growth, conservation, release, and reorganization. For Chiba Prefecture, these phases can be observed in urban expansion strategies that integrate flood risk assessments during growth; long-term infrastructural investments and environmental preservation in the conservation phase; the activation of emergency protocols during sudden flood events; and post-disaster evaluations that contribute to policy learning and reorganization. This cyclical perspective underscores the need for adaptive governance structures that evolve in response to both predictable and unforeseen hydrological challenges.

The various planning theories offer significant perspectives on flood management and decision-making. These distinct theories provide a structure to evaluate elements such as stakeholder involvement, power relations, and community values.

Table 1. Flood Management-related Planning Theories.

Planning Theory	Key Elements	Relevance to Flood Management
Rational planning	Systematic and logical approach, clear goals, identification of alternatives, and evaluation of outcomes	Conducting flood risk assessments, analyzing the cost-effectiveness of measures, and selecting efficient solutions
Incremental planning	Adaptive and iterative approach, flexibility, and responsiveness to changing conditions	Developing flexible flood management plans and adjusting strategies based on new information
Advocacy planning	Representing diverse stakeholder interests and advocating for vulnerable communities	Ensuring marginalized communities’ voices are heard in flood management decision-making
Communicative planning	Dialogue and collaboration among stakeholders and a shared understanding of flood risk	Building consensus on flood management strategies and fostering collective action
Radical planning	Transformative and community-based solutions addressing the root causes of vulnerability	Empowering communities to take control of their flood management strategies
Collaborative planning	Partnerships, shared decision-making, and coordination among diverse stakeholders	Fostering collaboration between government agencies, community groups, and private sector actors

outlines the main elements of the diverse planning theories and their applicability to flood management. As there are only few studies that have directly applied the planning theory to flood management policy analysis, this study is a new contribution. We continued with management-related planning theories in Table 1 and created an analytical framework that relates departmental flood management activities in Chiba Prefecture to the main features of rational, incremental, advocacy, communicative, radical, and collaborative planning. Our justification for this method is the coding and interpretation of 23 statutory documents, which disclose how departments implement theoretical principles in policy design, e.g., systematic assessment (rational), adaptation and policy iteration (incremental), and stakeholder engagement as a group of activities that can be empowered by (advocacy, communicative and collaborative) planning (priority). These instances signify the practical side of planning theory and its current usage in flood risk management in Chiba Prefecture.

Incorporating social learning theories and collaborative planning deepens the dialogue on flood resilience by emphasizing stakeholder engagement and multi-directional knowledge flows. Forester [23] and Innes and Booher [24] suggest that fostering trust-building, communication, and mutual learning among government agencies, technical experts, and local communities is crucial for developing adaptive, resilient flood management systems. In Chiba, this approach manifests through participatory practices such as community drills, local knowledge integration, and platforms for technical dialogue that collectively enhance the robustness of flood defenses. The interplay between these practices and the broader socio-hydrological context creates an environment where policy interventions are continuously refined to address the immediate and systemic dimensions of flood risk.

Through the lens of urban water-sensitive design [19], sustainability further refines this integrated approach by balancing economic growth, environmental stewardship, and social equity. Governmental flood management policies are evaluated based on their capacity to mitigate flood impacts and their long-term contributions to environmental health, community resilience, and regional development [19]. This holistic view aligns with the evolving recognition that effective flood management must transcend traditional engineering paradigms, embracing nature-based solutions and innovative participatory frameworks that address complex socio-ecological challenges.

The local region’s dual-pronged approach exemplifies how technological engineering-based solutions and nature-based, non-structural measures can complement each other when framed within the theoretical constructs of resilience, sustainability, and public participation. The rapid responsiveness of structural interventions during flood events aligns with the release phase in the Panarchy model [25], while the enduring benefits of ecological restoration and evidentiary policy adaptations enhance the conservation phase of the cycle. This synergy mitigates immediate hazards and promotes long-term adaptive capacity by enabling communities and ecosystems to learn, adjust, and reorganize in response to evolving flood risks.

Integrating these solutions underscores a broader, multi-scalar strategy supporting sustainable urban development as highlighted by water-sensitive urban design principles [19] and reinforces a participative planning process that values stakeholder engagement and collaborative governance. While structural interventions protect critical assets and support urban infrastructure, non-structural solutions emphasize community resilience and environmental stewardship. Our research case site of the Chiba Prefecture faces the compounded challenges of urbanization and climate-induced variability; its blended approach, combining engineered resilience and nature-based innovation, offers a comprehensive model for flood mitigation that addresses both immediate vulnerabilities and long-term sustainability goals.

Current flood management strategies could be enhanced by deepening cross-departmental coordination, expanding digital monitoring tools, and institutionalizing real-time learning and adaptation mechanisms [4]. Continuous refinement will ensure that structural and non-structural solutions evolve to meet the dynamic demands of urban flood resilience, setting a noteworthy example for regions facing similar hydrological challenges. By linking these theoretical insights with empirical patterns observed in policy statutory documents, the study offers a comprehensive model for adaptive flood management that others facing similar challenges might consider. Exploring mechanisms to further integrate digital tools for real-time content data collection, enhancing cross-departmental learning, and deepening community engagement will be critical in evolving these strategies into a resilient, responsive urban governance framework [5].

3. Methodology

Our descriptive and narrative content analysis of Chiba Prefecture’s flood management policies and plans relies on data sources, including official statutory government documents, policy reports, and public statements. We assess how planning concepts like resilience, sustainability, and public participation are reflected in the prefecture’s approach to flood risk mitigation.

3.1. Research Site

Located in the Kanto region of Japan (Figure 2), Chiba Prefecture is a dynamic area characterized by urban growth, significant precipitation, and vulnerability to natural disasters. Its population is approximately 6.27 million as of 2023, with urban centers like Chiba City and Funabashi driving demographic expansion [28]. The prefecture experiences an average annual rainfall of 1249.8 mm (Figure 3 and

Table 2. Chiba Prefecture: Monthly Rainfall by Year (2015–2024). (Source: https://www.data.jma.go.jp/stats, accessed on 4 June 2025).

Year	Jan.	Feb.	Mar.	Apr.	May.	Jun.	Jul.	Aug.	Sep.	Oct.	Nov.	Dec.
2015	55.5	48.5	105.5	40.0	82.0	132.0	205.5	20.5	103.5	182.5	62.5	110.0
2016	118.5	115.5	40.0	82.5	41.5	146.0	154.0	112.0	316.0	132.5	129.5	34.5
2017	47.5	37.5	43.0	68.5	33.0	86.5	97.0	70.0	115.0	104.0	177.5	153.0
2018	122.0	75.0	95.5	32.0	102.0	114.0	121.5	94.0	56.0	160.0	70.0	72.0
2019	56.0	46.5	35.5	11.0	48.0	48.5	88.0	163.5	36.5	55.0	69.0	91.5
2020	35.0	39.5	54.0	42.5	63.0	98.0	68.5	332.0	112.5	168.0	140.0	68.5
2021	101.5	111.5	40.5	78.0	73.0	17.5	6.0	47.0	51.0	167.5	157.5	210.5
2022	90.5	31.5	45.0	44.5	65.0	69.0	44.0	92.5	165.5	143.5	194.0	86.0
2023	108.5	67.5	38.0	99.5	21.5	90.5	145.5	318.0	87.5	143.0	295.5	141.5
2024	108.5	52.0	54.0	19.0	136.0	106.0	87.0	201.5	87.5	81.0	154.0	138.0

), concentrated during Japan’s rainy and typhoon seasons, contributing to its extensive river systems. Chiba is prone to flooding and coastal damage due to heavy rainfall and storm surges, as evidenced by historical events since the 1950s. River basin management has evolved significantly, especially after the 1997 amendment to Japan’s River Law, which emphasized environmental conservation alongside flood control [29]. Public awareness of sustainable development has fostered initiatives like green infrastructure projects in Matsudo. Balancing urbanization with ecological preservation remains central to Chiba’s regional planning efforts.

3.2. SETS Setting for Keyword Coding

The 23 governmental planning documents that were examined in this research have been chosen via a systematic review procedure which aims to ensure the policy relevance, both direct and indirect, of those documents, to the management of urban floods in Chiba Prefecture. The first criterion for inclusion was that the document had been issued by administrative departments responsible for flood risk governance, infrastructure, or environmental management. The second was that the document was valid and enacted between 2020 and 2024 to reflect contemporary policy responses. The third criterion was that the document should be demonstrably influential in shaping approaches to flood prevention, preparedness, response, or post-flood recovery. In addition, the selection was also used to consider the diversity of themes, explicitly including the plans for the three groups of intervention, that is, structural measures (e.g., engineering solutions), non-structural measures (e.g., public participation, education), and nature-based interventions.

In our keyword coding analysis using the SETS framework established by Chang et al. [5], S1 is the social dimension, focused on emergency planning and response measures such as evacuation, safety warnings, and public health services; S2 covers one-way knowledge and know-how transfer through public communication and educational outreach on flood risks; and S3 includes normative practices, best management guidelines, and informal economic strategies like insurance and cost–benefit analyses that support flood resilience. On the ecological side, E1 emphasizes ecosystem conservation, protection, and restoration, enhancing natural self-regulatory capacities through efforts like wetland management and habitat connectivity; E2 incorporates green infrastructure and ecological engineering approaches such as the installation of green roofs and urban greening to mitigate flood impacts; and E3 attends to the maintenance of ecological services that ensure natural drainage and coastal protection. In the technical realm, T1 is concerned with technical design aspects, including the development of improved building codes and flood control designs; T2 addresses the construction, maintenance, and operational management of engineered infrastructure such as dams, levees, and floodwalls; and T3 focuses on innovative technical solutions that leverage early warning systems, data monitoring, simulation, and risk analysis to manage flood events proactively.

To visually compare the relative emphasis on the social (S), ecological (E), and technological (T) dimensions across 23 planning documents, we first applied a normalization procedure to the results before plotting them in the triangular diagram. For each document, the raw percentage scores for S, E, and T (based on the SETS keyword coding) were adjusted proportionally so that their sum equals 1 (i.e., S + E + T = 1). This change standardizes the values, which means that all data points can be shown on a common scale regardless of the absolute number of keyword frequencies. The normalized triplets were then changed into Cartesian coordinates that are suitable for positioning in the ternary plot, where the three apices represent 100% focus on one dimension and 0% for the other two. This method makes sure that differences in position on the chart reflect only the relative balance among S, E, and T variables, thus providing easy visual comparison between documents and departments. For each department and statutory plan, the proportion of keywords categorized under Social (S), Ecological (E), and Technological (T) dimensions was calculated using the formula:

$$S={\displaystyle \frac{\mathrm{Number} \mathrm{of} \mathrm{S} \mathrm{keywords}}{\mathrm{Total} \mathrm{keywords}}}, E={\displaystyle \frac{\mathrm{Number} \mathrm{of} \mathrm{E} \mathrm{keywords}}{\mathrm{Total} \mathrm{keywords}}}, T={\displaystyle \frac{\mathrm{Number} \mathrm{of} \mathrm{T} \mathrm{keywords}}{\mathrm{Total} \mathrm{keywords}}}$$

To facilitate graphical analysis, these SETS values were normalized to sum to one for each data point:

$$S_{norm}={\displaystyle \frac{S}{S+E+T}}, E_{norm}={\displaystyle \frac{E}{S+E+T}}, T_{norm}={\displaystyle \frac{T}{S+E+T}}$$

For the ternary plot, each normalized SETS profile was mapped to Cartesian coordinates using:

$$x=0.5\times (2E_{norm}+T_{norm}), y={\displaystyle \frac{\sqrt{3}}{2}}\times T_{norm}$$

This enabled comparative visualization of flood management orientations across departments within Chiba Prefecture.

In order to authenticate our method more thoroughly, we have included significant citations that not only support the conceptual basis of the SETS framework but also demonstrate its practical usage. The findings of Chang et al. [5], Markolf et al. [6], and McPhearson et al. [30] are relevant in this context as they show the application of SETS in the areas of urban systems, environmental change, and disaster risk, respectively. These research works demonstrate the framework’s capacity to capture the interconnected dynamics of social, ecological, and technological domains in addressing complex urban challenges. By situating our study within this emerging body of scholarship, we reinforce the legitimacy of applying SETS as an analytical lens for flood risk governance.

This study adopts a novel and integrated approach by combining socio-hydrology with established planning theories, forming a robust conceptual framework for analyzing flood management policies. We carefully defined essential concepts by drawing upon the rich insights offered by socio-hydrology—an area that explores the interplay between human dynamics and water systems—and a broad spectrum of planning theories that address community resilience, infrastructure development, and environmental policy. This synthesis provided a unique analytical lens, ensuring our framework captures the complex interdependence between ecological processes and socio-political decision-making. Next, we employed the SETS framework to guide our analysis. This step involved a systematic review of 23 statutory planning documents, where we meticulously identified and coded keywords according to social, ecological, and technical classifications. Each document was analyzed individually, and the frequency of these keywords was calculated per document, allowing us to quantify the emphasis placed on various aspects of flood management across different texts. We aggregated the keyword counts by issuing departments, which allowed us to compile a comprehensive overall frequency for Chiba Prefecture. This quantitative assessment revealed current policy trends and serves as the basis for recommendations to improve flood management strategies. We align policy recommendations with existing practices and emerging environmental challenges, ensuring relevance and adaptability in a rapidly changing world (Figure 4).

4. Results

Table 3. SETS Keyword Code Frequency Ranking and Percentage for the Chiba Prefecture.

Rank	SETS Codes	Percentage of Keywords
1	E1 (Ecosystem conservation, natural resource protection and restoration)	20.70%
2	E2 (Green infrastructure and ecological engineering)	14.40%
3	S3 (Forecasting and informal practices)	12.53%
4	S1 (Emergency planning/preparedness/management)	12.49%
5	T2 (Engineering infrastructure facilities)	12.30%
6	S2 (Knowledge and know-how transfer)	10.02%
7	T3 (Technical solutions)	8.18%
8	E3 (Ecological services)	5.61%
9	T1 (Technical design)	3.76%

summarizes the SETS keyword coding results from our analysis of Chiba Prefecture’s statutory documents. We employed the SETS framework—with its dimensions defined as Social (S1, S2, S3), Ecological (E1, E2, E3), and Technical (T1, T2, T3)—to systematically classify and quantify flood management policy trends based on keyword frequencies (Table 3). The table shows the distribution of SETS categories across all documents.

The comprehensive analysis of SETS coding distribution highlights Chiba Prefecture’s strategic emphasis on ecological approaches to flood management, as evidenced by the substantial representation of the E1 and E2 categories (Figure 5). E1 (20.70%) emerges as the dominant factor, emphasizing ecosystem conservation, restoration, and natural resource protection, reflecting the region’s prioritization of sustainable environmental practices. Similarly, E2 (14.40%), associated with green infrastructure and ecological engineering, demonstrates a significant commitment to integrating nature-based solutions within policy frameworks. Social dimensions, notably S3 at 12.53% and S1 at 12.49%, underscore the importance of community resilience and adaptive strategies. Moderate attention is allocated to technical infrastructure (T2 at 12.30%) and knowledge transfer (S2 at 10.02%), indicating the need for practical, educational, and engineering measures. The relatively low emphasis on technical design (T1 at 3.76%) and ecosystem services management (E3 at 5.61%) suggests that while technical solutions are vital, they play a supporting role compared to ecological and social priorities. Chiba Prefecture’s flood management policies reveal a clear orientation toward ecological measures (40.72%), with social strategies comprising 35.04% and technical interventions 24.24%. This distribution highlights a balanced approach, integrating environmental sustainability, community engagement, and infrastructure development to address flood-related challenges effectively.

For this study, the legal or statutory planning documents were triangulated using various governmental agencies to ensure that they conform to the policy standards for the year 2024. Because of continuous policy changes, the report would have been very detailed if each publication date was mentioned. Instead, the focus is on those documents that are actively used in 2024 flood risk governance. The majority of the documents were issued between 2020 and 2024, with some departments having different issuance periods. Hence our analysis is largely dependent on the latest documents from each department, which is an indication of the government’s strategies for flood management in Chiba Prefecture.

Our SETS analysis of 23 statutory planning documents in Chiba Prefecture, Japan, uncovered significant flood management policy patterns, highlighting how different governmental departments adopt diverse yet interconnected approaches to address flood risks. Our analysis revealed a progressive shift toward ecological approaches, particularly ecosystem conservation, natural resource protection, and green infrastructure. This orientation represents an evolution from traditional technical flood control measures toward more sustainable, nature-based solutions. Chiba Prefecture’s flood management policies demonstrate a pronounced ecological orientation, with ecosystem conservation (E1) and green infrastructure (E2) collectively constituting 35.1% of all coded keywords across 23 statutory documents. This ecological emphasis coexists with substantial attention to social dimensions (S1–S3: 35.0%) and technical infrastructure (T2: 12.3%), revealing a multi-scalar approach to flood risk mitigation. Our results highlight significant departmental variations, with the Department of Land Improvement prioritizing green infrastructure (32.5%) while the Department of Disaster Management focuses on ecosystem conservation (34.9%). These policy orientations reflect Chiba’s integrated strategy of blending nature-based solutions with conventional engineering approaches, as other regions have done.

The coding results from analyzing individual statutory plans distinguish distinct policy orientations, reflecting the multifaceted nature of flood management in Chiba Prefecture (

Table 4. SETS Coding Results by 23 Statutory Plan Documents of Chiba Prefecture.

	S1	S2	S3	E1	E2	E3	T1	T2	T3
Regional Commercialization Plan (Dept. of Commerce)	12.5	12.5	14.0625	10.9375	10.9375	9.375	10.9375	10.9375	7.8125
Disaster Management Plan (Dept. of Disaster Management)	1.923076923	1.923076923	40.38461538	28.84615385	1.923076923	21.15384615	0	3.846153846	0
Resilience Plan (Dept. of Disaster Management)	14.73684211	17.89473684	9.473684211	41.05263158	2.105263158	5.263157895	2.105263158	5.263157895	2.105263158
Environmental Plan (Dept. of Environment)	17.1875	7.8125	14.0625	12.5	14.0625	7.8125	9.375	15.625	1.5625
SDGs (Dept. of General Affairs)	7.317073171	12.19512195	19.51219512	14.63414634	26.82926829	4.87804878	0	12.19512195	2.43902439
Building Management (Dept. of General Affairs)	16.66666667	10	23.33333333	16.66666667	10	6.666666667	0	16.66666667	0
Public Facility Management (Dept. of General Affairs)	12.12121212	12.12121212	18.18181818	21.21212121	10.60606061	10.60606061	1.515151515	10.60606061	3.03030303
Digital City Plan (Dept. of General Affairs)	8.695652174	7.246376812	13.04347826	18.84057971	15.94202899	4.347826087	7.246376812	21.73913043	2.898550725
Flood Control Plan (Dept. of General Affairs)	11.32075472	18.86792453	13.20754717	24.52830189	0	3.773584906	5.660377358	13.20754717	9.433962264
Women’s Job Seeking Support Plan (Dept. of General Affairs)	0	0	0	0	13.33333333	0	0	26.66666667	60
Childcare support plan (Dept. of General Affairs)	0	0	11.76470588	52.94117647	0	5.882352941	0	0	29.41176471
Ichinomiya Watershed Plan (Dept. of General Affairs)	20.68965517	13.79310345	6.896551724	20.68965517	13.79310345	0	0	17.24137931	6.896551724
Human Resources Development Support Plan (Dept. of General Affairs)	7.407407407	0	11.11111111	14.81481481	22.22222222	0	3.703703704	14.81481481	25.92592593
Employment Support Plan for Disabled Employees (Dept. of General Affairs)	29.41176471	11.76470588	0	44.11764706	0	0	11.76470588	2.941176471	0
Financial Resources Plan (Dept. of General Affairs)	16.66666667	16.66666667	0	20.83333333	8.333333333	8.333333333	8.333333333	12.5	8.333333333
Airport Plan (Dept. of General Planning)	8.333333333	11.11111111	19.44444444	33.33333333	5.555555556	8.333333333	5.555555556	8.333333333	0
Water Resource Plan (Dept. of General Planning)	17.24137931	10.34482759	6.896551724	6.896551724	34.48275862	0	3.448275862	13.79310345	6.896551724
Regional Development Plan (Dept. of General Planning)	16.12903226	6.451612903	6.451612903	22.58064516	12.90322581	6.451612903	6.451612903	16.12903226	6.451612903
Land Use Plan (Dept. of General Planning)	9.090909091	9.090909091	13.63636364	7.575757576	19.6969697	12.12121212	3.03030303	18.18181818	7.575757576
Prefecture Comprehensive Plan (Dept. of General Planning)	13.51351351	8.108108108	16.21621622	24.32432432	10.81081081	5.405405405	5.405405405	10.81081081	5.405405405
Development Plan (Dept. of Land Improvement)	14.28571429	26.53061224	5.102040816	20.40816327	23.46938776	0	2.040816327	6.12244898	2.040816327
Flood Prevention Plan (Dept. of Land Improvement)	19.51219512	9.756097561	9.756097561	12.19512195	36.58536585	2.43902439	0	9.756097561	0
Chiba Improvement Plan (Dept. of Land Improvement)	12.5	6.25	15.625	6.25	37.5	6.25	0	15.625	0

). Plans with a strong ecological focus include the Employment Support Plan for Disabled Employees (44.12% for E1), the Resilience Plan (41.05% for E1), the Flood Prevention Plan (36.59% for E2), the Chiba Improvement Plan (37.5% for E2), and the Airport Plan (33.33% for E1). Socially focused plans emphasize forecasting and informal practices (S3), as seen in the Disaster Management Plan (40.38%) and Building Management Plan (23.33%), while the Regional Development Plan allocates 26.53% to knowledge and know-how transfer (S2). Technical focus is evident in the Childcare Support Plan (60% for T3 and 26.67% for T2), the Human Resources Development Support Plan (25.93% for T3), and the Digital City Plan (21.74% for T2). These diverse SETS orientations demonstrate how organizational missions shape policy approaches, with specialized departments addressing unique objectives. Despite these variations, a coordinated preference for ecological strategies across multiple plans suggests a unified policy direction at the prefectural level, emphasizing ecosystem conservation and green infrastructure to enhance flood resilience. This integrated approach reflects Chiba Prefecture’s acknowledgment of the complexity of flood management and the need for complementary strategies, aligning with global trends favoring sustainable practices that balance social, ecological, and technical considerations. The progressive strategy implemented by Chiba Prefecture recognizes the limitations of purely technical solutions and leverages ecological systems to strengthen resilience, providing a model for holistic and adaptive flood management.

When analyzed by the responsible department—namely the Departments of Commercialization, Disaster Management, Environment, General Affairs, General Planning, and Land Improvement—distinct patterns in policy focus and SETS orientation emerge, revealing how mandates shape flood management strategies. The Department of Disaster Management exhibits the strongest ecological orientation among all departments, with ecosystem conservation (E1) representing 34.95% of its policy content; this is followed by forecasting and informal practices (S3) at 24.93%, indicating a fundamental shift from traditional technical approaches to nature-based solutions. The Department of Land Improvement demonstrates a strategic focus on green infrastructure and ecological engineering (E2), dedicating 32.52% of its policy content to this category, the highest among all departments. The department also emphasizes emergency planning (S1) at 15.4%, blending sustainable land development with disaster preparedness.

The Department of Commercialization takes a balanced approach across all SETS categories, with forecasting and informal practices (S3) slightly leading at 14.06% and equal attention to emergency planning (S1) and institutional management (S2) at 12.5%. This pragmatic strategy reflects its integrative focus in commercial contexts. The Department of General Affairs, responsible for overseeing diverse administrative plans, prioritizes ecosystem conservation (E1) at 22.66% while giving notable attention to technical solutions (T3) and engineering infrastructure (T2), both at 13.5%, signaling its comprehensive scope in addressing flood management needs.

The Department of General Planning focuses on ecological approaches, emphasizing ecosystem conservation (E1) at 18.94% and green infrastructure (E2) at 16.69%. This balanced distribution reflects an effort to integrate various ecological considerations into planning strategies. Expectedly, the Department of Environment places its highest emphasis on emergency planning and preparedness (S1) at 17.19% while maintaining relatively substantial contributions to green infrastructure (E2) and forecasting/informal practices (S3), each at 14.06%. This dual focus underscores its commitment to ecological and social priorities.

These profiles highlight the diverse approaches taken by departments in flood management, with some emphasizing ecological sustainability while others integrate technical solutions or infrastructure strategies. By leveraging strengths such as the Land Improvement Department’s focus on green infrastructure and the Disaster Management Department’s ecological orientation, future policies could foster interoperable frameworks, transforming fragmented strategies into an adaptive flood resilience network. Figure 6 displays our results in a triangular plot, a specialized visualization tool that illustrates the relative proportions of three variables in a two-dimensional space. This graph is particularly beneficial when the aggregate of three variables remains constant, often 1 or 100%. Each vertex signifies an extreme condition when one variable is 100% while both of the other two variables are 0%. The aggregate of the three variables’ values remains constant at every point on the graph, but the locations of the dots indicate the relative proportions among the three variables. We normalized the S, E, and T values for each data point to ascertain the location of a data point on a triangle graph. This results in S + E + T = 1 for every point. The normalized triangular coordinate is converted into a Cartesian coordinate system (x, y) and shown on a two-dimensional plane.

Our triangular graph visualizes the relative proportions of S, E, and T for six different departments, with each department represented by a distinct color and labeled in the legend. Each vertex of the triangle corresponds to 100% of one variable (S, E, or T), and the position of each department within the triangle reflects its unique balance among these three factors. Departments closer to a particular vertex have a higher proportion of that variable. The Department of Disaster Management is closer to the E vertex, indicating a strong emphasis on E; meanwhile, the Department of Commercialization and the Department of Environment are more centrally located, suggesting a more balanced distribution among S, E, and T. The Department of Land Improvement is nearer to the S vertex, showing a higher S proportion. This plot allows for a quick visual comparison of how each department prioritizes or balances the three variables, highlighting similarities and differences in their profiles.

The SETS keyword coding of 23 statutory plans from Chiba Prefecture reveals a significant overall orientation toward Ecological approaches (E1 and E2), particularly ecosystem conservation, restoration, and green infrastructure, in addressing flood management. Social dimensions—encompassing emergency planning (S1) and normative/economic measures (S3)—alongside technological infrastructure and operations (T2), are also key components of the strategy. However, there is considerable variation at the departmental level, reflecting the specific mandates and perspectives of different administrative bodies. The Department of Disaster Management heavily integrates ecosystem-based approaches (E1) with normative/economic strategies (S3), while the Department of Land Improvement strongly emphasizes green infrastructure implementation (E2). Our analysis highlights a multifaceted approach to flood management in Chiba, with a notable tendency toward integrating ecological principles into planning frameworks. This nuanced distribution provides valuable insights into how statutory plans can be comprehensive and specialized, aligning departmental mandates with broader ecological and societal objectives in flood management.

5. Discussions

5.1. Overview of Key Findings

The SETS coding results reveal a clear policy trend in Chiba Prefecture’s flood management strategies. The overall data suggest that ecological measures, particularly those related to ecosystem conservation (E1) and ecological engineering (E2), are prioritized above all other dimensions. This pattern likely reflects the recognition that sustainable flood management increasingly relies on nature-based solutions that enhance ecological resilience. At the document level, there is notable heterogeneity—the Disaster Management Plan, for example, emphasizes normative practices (S3) and ecosystem preservation (E1) to address immediate hazards. In contrast, documents like the Regional Commercialization Plan exhibit a more balanced integration of social, ecological, and technical components. Such differences highlight the nuanced mandates and operational priorities of different legal instruments.

The departmental breakdown of the SETS profiles reinforces the notion that institutional perspectives shape policy formulation. The Department of Disaster Management is markedly oriented toward emergency and ecosystem measures, while the Department of Land Improvement prioritizes ecological engineering (E2) alongside social planning (S1). In contrast, the Department of General Affairs appears to adopt a more balanced approach with elevated attention to data-driven technical interventions (T3) and overall ecosystem management (E1). Applying the SETS framework enables a systematic and comparative evaluation of regional flood management policies, illuminating the dominant policy trends—chiefly the emphasis on ecological approaches—and facilitating the identification of inter-departmental variations. Such insights are invaluable for policymakers seeking to harmonize flood management strategies and scholars aiming to understand the multi-dimensional nature of disaster policy formulation.

Framing these results through planning theory illuminates additional insights into the design and execution of these policies [25]. The Panarchy model offers a valuable framework for understanding the cyclical phases—growth, conservation, release, and reorganization—that underpin the dynamics of coupled human–water systems. In Chiba’s context, the growth phase is evident in urban expansion strategies that integrate flood risk assessments, while the conservation phase manifests through sustained investment in flood control infrastructure and ecological conservation. The release phase is observed during flood events when emergency protocols, such as evacuation plans, are activated, and reorganization occurs through post-disaster assessments and policy revisions. The strong ecological emphasis identified via SETS coding suggests that Chiba’s policies are particularly committed to the conservation phase, preserving and restoring natural elements that enhance system resilience and facilitate adaptive reorganization after flood events [25].

5.2. Integration of Planning Theory and SETS Framework

Applying collaborative planning theories, as advanced by Forester [23] and Innes and Booher [24], underscores the value of stakeholder engagement and community-based decision-making in flood management. Chiba’s policy ensemble, evidenced by the integration of community drills, public knowledge transfer (S2), and socio-technical innovations in the Digital City Plan, demonstrates an emerging commitment to participatory practices. These practices are essential for creating shared understanding and trust among diverse actors, enabling more adaptive, resilient urban systems. The relatively low allocation to technical design (T1) suggests that despite progress toward decentralizing and democratizing planning efforts, there remains a gap in advancing innovative technological solutions. While collaborative planning creates a platform for dialogue and inclusion, effectively translating such dialogue into transformative technical innovations requires further development [23,24].

The heterogeneity in SETS profiles across departments reveals an incremental planning approach operating alongside the dominant rational-ecological framework. Lindblom’s [31] concept of “muddling through” is evident in how different departments have developed specialized approaches based on their institutional mandates rather than following a single comprehensive blueprint. The Department of Commercialization’s balanced distribution across SETS categories (with S3 at 14.06% and equal attention to S1 and S2 at 12.5%) exemplifies this incremental adaptation to specific contexts and responsibilities. The Department of Disaster Management prioritizes ecosystem conservation (E1) and emergency preparedness (S1), whereas the Department of Land Improvement exhibits a strong commitment to ecological engineering (E2) paired with social planning. In contrast, the Department of General Affairs opts for a more balanced approach, incorporating ecological measures and data-driven technical interventions (T3). Such variations suggest that while Chiba’s overall policy direction favors ecological solutions, institutional mandates and operational objectives shape differentiated approaches across departments.

By better harmonizing these inter-departmental strategies—through enhanced collaboration and data integration—Chiba Prefecture could develop its flood management policies into a more resilient and adaptive framework. This synchronization would further embody the cyclic processes posited by the Panarchy model and the inclusive dynamics championed by collaborative planning theories, ultimately fostering a governance regime that is sustainable and responsive to evolving flood risks. This departmental specialization has advantages in allowing tailored responses to different aspects of flood management. However, it also risks creating policy silos that may impede integrated watershed management, which is crucial for effective flood governance [27]. The challenge for Chiba Prefecture is maintaining departmental expertise while ensuring cross-sectoral coordination.

Despite the ecological orientation, Chiba Prefecture’s flood management approach shows limited implementation of communicative planning principles. Communicative planning theory emphasizes stakeholder dialogue, collaborative problem-solving, and the integration of diverse knowledge systems [24]. The relatively modest allocation to S2 (knowledge and know-how transfer) at 10.02% across all documents suggests that genuine two-way communication and collaborative knowledge production may be underdeveloped while information dissemination occurs. This gap is particularly notable given Japan’s vulnerability to flooding and the importance of local knowledge in effective disaster response [12,32]. The Human Resources Development Plan’s emphasis on S2 (26.5%) represents a positive exception, but the overall pattern suggests that Chiba’s flood management remains primarily expert-driven rather than collaboratively constructed with communities.

The SETS analysis of Chiba Prefecture’s flood management policies reveals a predominantly rational planning approach with a strong ecological orientation, a significant evolution from traditional engineering-focused flood control strategies toward more sustainable, nature-based solutions. The SETS coding analysis reveals that Chiba Prefecture’s flood management policies predominantly follow a rational planning model characterized by systematic problem-solving approaches and evidence-based decision-making [26]. However, this rational planning framework is oriented toward ecological green solutions rather than purely technical ones, representing an evolution from Japan’s historically engineering-dominated flood control strategies [33]. This shift aligns with global trends, recognizing the limitations of purely structural measures and the value of ecosystem-based approaches to flood resilience.

The strong emphasis on E1 (ecosystem conservation) and E2 (green infrastructure) across departments suggests a deliberate policy direction incorporating ecological rationality into the traditional rational planning framework. Integrating ecological principles into planning represents an advanced understanding of socio-ecological systems and their resilience [18]. The Department of Disaster Management’s focus on ecosystem conservation (34.95%) and the Department of Land Improvement’s emphasis on green infrastructure (32.52%) exemplify this ecological rationality.

5.3. Local Application: Insights from Chiba Prefecture

There are several opportunities to strengthen communicative, integrated, and adaptive planning elements to enhance the effectiveness, equity, and resilience of flood management in the face of increasing climate-related risks. By addressing these gaps while maintaining its ecological focus, Chiba Prefecture can develop a more comprehensive and balanced approach to flood management that integrates social, ecological, and technical considerations. This approach enhances flood resilience and serves as a model for other regions facing similar climate change and urbanization challenges.

Our synthesis of SETS coding results with planning theory reveals that Chiba Prefecture’s flood management policies increasingly conform to nature-based solutions prioritizing ecological resilience. While significant resources are devoted to ecosystem conservation and green infrastructure, there is a continued need to integrate innovative technical designs and further institutionalize participatory planning processes. Future improvements should develop frameworks that enhance inter-departmental collaboration, incorporate real-time data for adaptive management, and amplify stakeholder engagement to achieve a more integrated and responsive flood management regime. Such an approach addresses imminent hazards and lays the groundwork for long-term resilience in the face of dynamic environmental challenges.

While not dominant, there are indications of adaptive planning principles emerging in Chiba’s flood management approach. Emphasizing flexibility, learning, and adjustment to changing conditions [17], adaptive planning is reflected in the attention to S3 (forecasting and informal practices) at 12.53% across all documents. The Disaster Management Plan’s high allocation to S3 (40.38%) suggests recognizing the need for adaptability in the face of climate change and increasing flood risks. This adaptive orientation is promising but remains constrained by the rational planning framework. A more fully developed adaptive approach would require stronger mechanisms for monitoring, evaluation, and policy adjustment based on outcomes and changing conditions [25].

To enhance the effectiveness and equity of its flood management, Chiba Prefecture should adopt a multifaceted approach that strengthens communicative planning elements, encourages cross-departmental integration, advances adaptive planning capabilities, and balances ecological and social dimensions. In practice, this means establishing formal mechanisms for community participation in flood risk assessment and management planning [23], creating platforms for dialogue between technical experts, policymakers, and local communities to integrate diverse knowledge systems [24], and developing collaborative governance structures that involve multiple stakeholders in decision-making processes [34]. While departmental specialization brings benefits, there is a need to institute formal coordination mechanisms across the various departments involved in flood management, develop shared planning frameworks that maintain departmental expertise without sacrificing policy coherence, and create integrated watershed management approaches that transcend administrative boundaries [19]. To better respond to climate change and increasing flood risk, the prefecture should implement robust monitoring systems to track the effectiveness of flood management measures, develop flexible policies that can be adjusted based on changing conditions and new information, and establish formal learning mechanisms that incorporate lessons from flood events [18]. Lastly, Chiba Prefecture should increase its focus on the social dimensions of flood risk management by prioritizing vulnerable populations and social equity, strengthening community capacity-building for flood preparedness and response, and developing comprehensive social resilience strategies that work synergistically with ecological approaches [35,36].

Even though this work has been specifically designed around the flood risk governance in Chiba Prefecture, the methodology and basic principles could be transferred to other places and different settings. The combination of the Social-Ecological-Technological Systems (SETS) model with planning theory has the advantage of being able to proceed with a systematic assessment of flood management strategies that are in harmony with the local ecological characteristics, societal needs, and technical (structural engineering) capacities (

Table 5. Summary of the Chiba Prefecture Flood Risk Management Framework.

Dimension/Component	Key Features	Department/Plan Examples	SETS Emphasis
Structural Measures	Flood embankments, river/channel improvements, drainage infrastructure, stormwater detention facilities	Land Improvement Dept: Flood Prevention Plan, Development Plan	Technological (T)
Non-Structural Measures	Land use zoning, regulatory planning, public education, early warning, evacuation systems	General Affairs Dept: Flood Control Plan, Digital City Plan	Social (S)
Nature-Based Solutions	Wetland restoration, green infrastructure, preservation of floodplains, ecosystem services	Environment Dept: Environmental Plan	Ecological (E)
Integrated Governance	Cross-sectoral coordination, participatory planning, multi-stakeholder engagement, knowledge sharing	SDGs Plan, Resilience Plan, Prefecture Comprehensive Plan	S/E/T Integration
Public Participation & Stakeholder Inclusion	Community involvement in drills, local knowledge integration, trust-building with authorities	Disaster Management Plan, Community Engagement Platforms	Strong Social (S)
Adaptation & Flexibility	Focus on both prevention and adaptation to increased risk (inc. climate impacts), scenario planning	Resilience Plan, Environmental Plan	Ecological + Social
Support for Vulnerable Populations	Focus on at-risk groups (elderly, children, disabled), inclusive recovery and preparedness strategies	Childcare Support Plan, Employment Support Plan	Social (S)
Technological Improvement	Smart monitoring, data sharing, digitalization of response systems, technical upgrades	Digital City Plan, Public Facility Management Plan	Technological (T)

).

To adapt this framework to other regions, the procedure that the workers and policymakers should follow is to gather the policy documents that fit the region, use the same SETS keyword coding technique, and then normalize the variables for the presentation of comparative department emphasis. This activity may assist in discovering the shortcomings or the strong points of flood governance [36]—for example, the lack of the ecological or social adaptation strategies that may be the focus areas in the strategies-thereby facilitating context-sensitive planning with the support of real data.

In a situation where climate risk, institutional arrangements, or development pressures are different, the SETS framework will still offer various degrees of adaptability [37], allowing the change in coding categories or the stakeholder engagement practices as per the requirements. The real advantage of this interdisciplinary, comparative model when applied across such diverse contexts [38] is that it becomes a vehicle for cross-regional learning, thus becoming a source of integrated flood management, and enabling resilient policy innovation under various geographical and administrative conditions.

As a way of solidifying the conceptual basis of this research work, we have broadened the background scope to include more substantial examples of SETS-informed approaches from other domains that are also ecologically close to urban climate adaptation, wildfire resilience, and sustainable water governance. These cases, although not all geographically or directly linked to flood risk management, depict the SETS framework as being a rather versatile tool for addressing intricate socio-environmental challenges. Depending on how far one takes the framework, one can see that its use is not limited to a particular context but can be very relevant and even transferable to many others. This is what we want to convey to our readers by giving examples of SETS application which in turn will make them realize its potential for dealing with the various facets of the risk management and resilience planning.

This research has presented findings that offer ways to improve flood risk management in Chiba Prefecture. First of all, local authorities, by the implementation of the SETS framework, can effectively facilitate policy coordination not only among such departments as disaster management, land improvement, and environmental protection but also build more integrated and adaptive flood strategies. These discoveries are highly compatible with the Japanese national frameworks such as the Basic Act on Disaster Management and the National Resilience Plan that advocate the idea of governance with the involvement of the community and cross-sector collaboration. Next, the establishment of joint working groups, the improvement of data-sharing mechanisms, and the involvement of different stakeholders in the planning and carrying out of activities are some of the institutional measures through which Chiba Prefecture can promote the links. Such steps will be helpful in ensuring the coherence between local and national policy objectives, thus advancing the resilience of the area to flood hazards.

6. Conclusions

This study highlights the critical importance of integrating planning theory into socio-hydrological models to enhance urban flood management; our case study of the Chiba Prefecture in Japan vividly demonstrates this connection. Our findings underscore the transformative potential of a holistic approach by bridging planning principles with the technical insights of socio-hydrology. This study synthesizes planning concepts—such as resilience, sustainability, and public participation—with advanced hydrological dynamics, moving beyond conventional engineering-centric flood control. Integrating these disciplines enables us to appreciate the interplay between human behaviors and natural water systems, which is essential when aiming for urban sustainability and a resilient built environment.

While discussing the aforementioned, we pointed out that the extent of using the SETS framework in flood risk management is still much undefined in the academic literature. One of the main reasons for this is the lack of research resulting from the inaccessibility of official, Japanese-language documents. Consequently, there have been no studies of flood governance in Japan that have been based on the SETS framework. By filling in this void, our research not only delivers fresh empirical observations but also demonstrates the real-world applicability of SETS in the study of an urban flooding case in Japan. Moreover, this study can provide a wider understanding of the issue, thus, attracting the attention of the public officials and the disaster managers in Japan, who can benefit from such an exposure in forming more integrative and future-oriented risk management strategies.

We applied the Panarchy model using the SETS framework, providing a structured lens to examine key policy documents systematically. This framework revealed that successful urban flood management strategies should rely on infrastructural fortifications and embrace nature-based solutions and ecological strategies. This implication means considering green infrastructure (e.g., permeable pavements, restored wetlands, and urban forests) as integral components of a flood risk management toolbox. These ecological strategies and social and technical innovations create a more comprehensive and adaptive urban planning paradigm that can dynamically respond to changing climatic conditions.

The case of Chiba Prefecture serves as a robust empirical model for other cities grappling with similar challenges. The multidisciplinary approach illustrated here shows that integrating public participation can further enhance community understanding and ownership of flood management measures. When communities are actively involved in planning and decision-making, the resulting strategies are naturally more equitable and tailored to local contexts. This strategy enhances safety during extreme weather events and cultivates livable communities that are better prepared for long-term climate variability.

In summary, for Chiba Prefecture in particular, our findings highlight the importance of balancing rapid urban development with proactive ecological and social strategies. The region’s vulnerability to typhoon-related flooding underscores the necessity of integrating planning theories with SETS-based analysis to manage competing land uses, coastal risks, and community safety needs. By aligning rational risk assessments with communicative and collaborative planning approaches, Chiba can foster inclusive decision-making and strengthen flood resilience across municipal departments. This case illustrates how place-specific planning, grounded in both technical expertise and community engagement, can serve as a model for other coastal urban regions facing intensifying climate challenges.

Though giving new data on reality, the study still has some limitations which are necessary to be mentioned. First of all, the research mostly depends on official planning documents that were issued in the period from 2020 to 2024. Such documents may not fully reflect the informal practices or the latest changes in policies that took place outside the official channels. Second, due to the case study’s geographical focus on Chiba Prefecture and reliance on Japanese-language resources, the findings’ broader generalizability to other areas may be limited. Last but not least, the SETS framework and planning theory offer a comprehensive perspective of the research; however, this study does not include primary stakeholder interviews or direct field observations, which could improve the quality and subtlety of the evaluation. Subsequent studies might want to overcome these limitations by incorporating more diverse data sources and conducting comparative studies in various locales.

While the present study lays a solid foundation, further research is needed to refine and extend these findings. Future studies should focus on developing more sophisticated socio-hydrological models that capture the complex feedback loops between human activities and water dynamics. Evaluating the effectiveness of various flood management strategies in achieving resilience, sustainability, and equity remains paramount. There is a pressing need to explore how emerging technologies and new data sources (e.g., real-time sensors and advanced remote sensing) can augment flood risk assessment and management. We can craft more effective and equitable solutions to the pressing global challenge of urban flooding by deepening our understanding of urban socio-hydrology. This strategy ensures that cities can respond to and recover from extreme weather events, fostering sustainable community development.